FileField provides a generic file upload field for content.module (CCK). It's supposed to be an alternative to upload.module in Drupal core, and provides a CCK field called "File" that you can use in your content types. For a more detailed description of module features and dependencies, please see its project page.
This handbook section exists to collect and encourage documentation on how to achieve specific tasks with FileField. If you solved a problem in a way that would also help other people get their stuff done, feel free to add walkthroughs, howto pages and other kinds of documentation as child pages of this one.